<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            border: 0;
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        :root {
            --hue: 0;
            --sat: 0%;
            --bg: hsl(var(--hue),var(--sat),90%);
            --fg: hsl(var(--hue),var(--sat),10%);
            --trans-dur: 0.3s;
            font-size: calc(16px + (24 - 16) * (100vw - 320px) / (2560 - 320));
        }
        body,
        button {
            color: var(--fg);
            font: 1em/1.5 -apple-system, BlinkMacSystemFont, "Helvetica Neue", Helvetica, sans-serif;
        }
        body {
            background-color: var(--bg);
            background-image: linear-gradient(-45deg,hsla(var(--hue),var(--sat),0%,0),hsla(var(--hue),var(--sat),0%,0.3));
            display: flex;
            height: 100vh;
            transition:
                    background-color var(--trans-dur),
                    color var(--trans-dur);
        }
        .keyboard,
        .keyboard:before,
        .keyboard:after {
            transition:
                    background-color var(--trans-dur),
                    box-shadow var(--trans-dur);
        }
        .keyboard,
        .keyboard__key-lines {
            display: flex;
        }
        .keyboard {
            background-color: hsl(var(--hue),var(--sat),80%);
            background-image: linear-gradient(90deg,hsla(var(--hue),var(--sat),10%,0.4),hsla(var(--hue),var(--sat),10%,0));
            border-radius: 0.75em;
            box-shadow:
                    -0.5em -0.5em 0.75em hsla(0,0%,0%,0.6),
                    0 0 0 1px hsl(var(--hue),var(--sat),67%) inset;
            align-items: center;
            margin: auto;
            padding: 0.375em;
            position: relative;
            width: 18.5em;
            height: 6.5em;
        }
        .keyboard:before,
        .keyboard:after {
            background-color: hsl(var(--hue),var(--sat),90%);
            content: "";
            display: block;
            position: absolute;
            bottom: 100%;
        }
        .keyboard:before {
            box-shadow:
                    -0.5em -0.5em 0.75em hsla(0,0%,0%,0.6),
                    0.25em 0 0.25em hsla(var(--hue),var(--sat),10%,0.2) inset,
                    0.25em -1.25em 0.5em hsla(var(--hue),var(--sat),10%,0.5) inset;
            left: calc(50% - 0.5em);
            width: 1em;
            height: 40em;
        }
        .keyboard:after {
            border-radius: 0.25em 0.25em 0 0;
            box-shadow: 0.375em -0.25em 0.5em hsla(var(--hue),var(--sat),10%,0.5) inset;
            left: calc(50% - 0.75em);
            width: 1.5em;
            height: 1.25em;
        }
        .keyboard__cmd {
            display: block;
            width: 1em;
            height: 1em;
        }
        .keyboard__key {
            background-color: hsl(var(--hue),var(--sat),95%);
            border-radius: 0.5em;
            box-shadow:
                    -0.4em -0.25em 0.25em hsla(0,0%,0%,0.25),
                    0 0 0 0.1em hsla(0,0%,0%,0.3),
                    0.04em 0.04em 0.04em hsla(0,0%,0%,0.4) inset,
                    -0.1em -0.1em 0.04em hsla(0,0%,100%,0.8) inset;
            color: hsl(var(--hue),var(--sat),50%);
            margin: 0 0.375em;
            outline: transparent;
            padding: 0.75em;
            position: relative;
            width: 5em;
            height: 5em;
            transition:
                    background-color var(--trans-dur),
                    box-shadow 0.15s,
                    color var(--trans-dur);
            -webkit-appearance: none;
            appearance: none;
            -webkit-user-select: none;
            -moz-user-select: none;
            user-select: none;
            -webkit-tap-highlight-color: transparent;
        }
        .keyboard__key--meta {
            width: 5.5em;
        }
        .keyboard__key:active,
        .keyboard__key.active {
            box-shadow:
                    0 0 0.2em hsla(0,0%,0%,0.2),
                    0 0 0 0.1em hsla(0,0%,0%,0.4),
                    0 -0.05em 0 hsla(0,0%,0%,0.6) inset,
                    -0.05em -0.15em 0.05em hsla(0,0%,100%,0.8) inset;
        }
        .keyboard__key-line {
            font-size: 2em;
            line-height: 1;
        }
        .keyboard__key-line--small {
            font-size: 0.875em;
        }
        .keyboard__key-line--tr {
            margin: 0 0 auto auto;
        }
        .keyboard__key-line--br {
            margin: auto 0 0 auto;
        }
        .keyboard__key-lines {
            display: flex;
            justify-content: center;
            align-items: center;
            flex-direction: column;
            width: 100%;
            height: 100%;
            transition: transform 0.15s;
        }
        .keyboard__key:active .keyboard__key-lines,
        .keyboard__key.active .keyboard__key-lines {
            transform: translateY(-1px);
        }
        .keyboard__key:before {
            box-shadow: 0 0 0 0.5em hsla(223,90%,50%,0);
            border-radius: 0.5em;
            content: "";
            display: block;
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            transition: box-shadow var(--trans-dur);
        }
        .keyboard__key:focus-visible:before {
            box-shadow: 0 0 0 0.5em hsla(223,90%,50%,0.5);
        }

        /* Dark theme */
        @media (prefers-color-scheme: dark) {
            :root {
                --bg: hsl(var(--hue),var(--sat),20%);
                --fg: hsl(var(--hue),var(--sat),90%);
            }
            .keyboard__key {
                background-color: hsl(var(--hue),var(--sat),15%);
                box-shadow:
                        -0.4em -0.25em 0.25em hsla(0,0%,0%,0.25),
                        0 0 0 0.1em hsla(0,0%,0%,0.3),
                        0.04em 0.04em 0.04em hsla(0,0%,0%,0.4) inset,
                        -0.1em -0.1em 0.04em hsla(0,0%,100%,0.05) inset;
                color: hsl(var(--hue),var(--sat),90%);
            }
            .keyboard__key:active,
            .keyboard__key.active {
                box-shadow:
                        0 0 0.2em hsla(0,0%,0%,0.2),
                        0 0 0 0.1em hsla(0,0%,0%,0.4),
                        0 -0.05em 0 hsla(0,0%,0%,0.4) inset,
                        -0.05em -0.15em 0.05em hsla(0,0%,100%,0.05) inset;
            }
        }
    </style>
</head>
<body>
<div class="keyboard">
    <button class="keyboard__key keyboard__key--meta" type="button" data-key="cmd">
		<span class="keyboard__key-lines">
			<svg class="keyboard__cmd keyboard__key-line--tr" viewBox="0 0 16 16" width="16px" height="16px" aria-hidden="true">
				<path fill="none" stroke="currentcolor" stroke-width="2" d="M5.7,10.3v2.3c0,1.3-1,2.3-2.3,2.3S1,14,1,12.7s1-2.3,2.3-2.3H5.7z M5.7,10.3h4.7 M5.7,10.3V5.7M10.3,10.3v2.3c0,1.3,1,2.3,2.3,2.3s2.3-1,2.3-2.3s-1-2.3-2.3-2.3H10.3z M10.3,10.3V5.7 M10.3,5.7H5.7 M10.3,5.7V3.3c0-1.3,1-2.3,2.3-2.3S15,2,15,3.3s-1,2.3-2.3,2.3H10.3z M5.7,5.7V3.3C5.7,2,4.6,1,3.3,1S1,2,1,3.3s1,2.3,2.3,2.3H5.7z" />
			</svg>
			<small class="keyboard__key-line keyboard__key-line--small keyboard__key-line--br">command</small>
		</span>
    </button>
    <button class="keyboard__key" type="button" data-key="c">
		<span class="keyboard__key-lines">
			<span class="keyboard__key-line">C</span>
		</span>
    </button>
    <button class="keyboard__key" type="button" data-key="v">
		<span class="keyboard__key-lines">
			<span class="keyboard__key-line">V</span>
		</span>
    </button>
</div>

<script>
    window.addEventListener("DOMContentLoaded",() => {
        const c = new CopypasteKeyboard(".keyboard");
    });

    class CopypasteKeyboard {
        constructor(el) {
            this.el = document.querySelector(el);

            this.init();
        }
        get isMac() {
            return /(Mac|iP[ahno]+[de])/i.test(navigator.userAgent);
        }
        init() {
            window.addEventListener("keydown",this.keyAction.bind(this,true));
            window.addEventListener("keyup",this.keyAction.bind(this,false));
        }
        keyAction(down,e) {
            let { key } = e;
            const isCmd = key === "Meta" && this.isMac;
            const isCtrl = key === "Control" && !this.isMac; // for non-Apple only

            if (isCmd || isCtrl) key = "cmd";

            const keyEl = this.el?.querySelector(`[data-key="${key}"]`);
            const activeClass = "active";

            if (down === true) keyEl?.classList.add(activeClass);
            else keyEl?.classList.remove(activeClass);
        }
    }
</script>
</body>
</html>